The overall goal of this project is to determine the mechanism of the altered cell surface and function of peripheral blood T lymphocytes in untreated and treated patients with Hodgkin's disease. In particular, we will attempt to characterize a serum factor found in these patients which specifically binds to and alters the function of T lymphocytes from patients with Hodgkin's disease, but not from normals or patients with other cancers. As of the last progress report, we had determined that the specific inhibitory factor in the serum of Hodgkin's patients was altered after admixture to a potassium bromide gradient, such that the inhibitory activity lost its specificity. The non-specific inhibitor was found in the LDL fraction of the serum after the KBr gradient separation. On the other hand, separation of the serum of a sucrose gradient showed that the specific inhibitory activity was preserved, but that the activity was not associated with the lipid fraction of the serum. Our most recent results show that the inhibitor obtained from the sucrose gradient can be further purified on the KBr gradient. The material obtained after the second gradient procedure is now associated with the lipid fraction of the serum, and maintains its specificity. The specific inhibitor was further purified by thin layer chromatography, and appears to be a glycolipid. A distinct rapidly migrating band which stains positively for hexose contains the inhibitory activity. This material is found in much greater quantity in Hodgkin's disease as compared to normal serum as determined by thin layer chromatography. The material runs with an Rf similar to that of galactose or glucose cerebroside. We are presently attempting to elucidate further the sugars and nature of the lipid on the material isolated by thin layer chromatography.